Pumping well tools through flowlines of irregular diameter



April 4, 1967 v E. D. YETMAN 3,31

PUMPING WELL TOOLS THROUGH FLOWLINES OF IRREGULAR DIAMETER Filed Jan.30, 1964 2 Sheets-Sheet 1 INVENTOR:

EDWARD D. YETMAN MK/77 W HIS ATTORNEY E. D. YETMAN A ril 4, 1967 PUMPINGWELL TOOLS THROUGH FLOWLINES OF IRREGULAR DIAMETER Filed Jan. 50, 1964 2Sheets-Sheet 2 FIG. 3

l NVENTOR Fl G. 2

N Aw m E E W W w m D T D A m w W H D E:

fiowline operation of underwater wells.

United States Patent ()fiice 3,312,232 Patented Apr. 4, 1967 3,312,282PUMPING WELL TQOLS THROUGH FLOWLTNES F IRREGULAR DIAMETER Edward D.Yetman, Bakersfield, Caliitl, assignor to Shell Oil Company, NewYork,'N.Y., a corporation of Delaware Filed Jan. 30, 1964, Ser. No.341,300 4 Claims. Cl. 166-46) This invention relates to well toolsadapted to be pumped through flowlines leading to underwater wellheadassemblies located on the ocean floor. More particularly, the inventionis directed to a means for installing well tools and retrieving themfrom well strings disposed in underwater wells throughirregular-diameter flowlines communicating with the wells.

The invention is especially suited for the through-the-Through-thefiowline operations refer to techniques wherein wellcompletion and operation procedures are conducted by tools which passthrough a fiowline communicating between a surface location, such as anoperating station, and a submerged well installation, movement of thetool being caused by pumping a driving fluid through the flowline. Inorder to carry out some of the more simple work-over or maintenanceoperations, such as the removal of a valve, the cleaning of paraflinfrom a tubing string, etc., there were developed an entirely new line ofwell tools which can be pumped through a production fiowline from someremote location, oftentimes a mile or more from the well, and enter thewell, passing down the tubing string therein to be subsequentlypositioned therein for carrying out some preselected operation. Aftercompleting the operation, the tool in the tubing string within the wellis subsequently removed, generally by reverse circulation of the drivingfluid. Examples of such operations and tools are shown in U.S. PatentsNos. 3,050,130 to Culver et al. and 3,090,440 to Lagucki.

Portions of the flowlines leading to underwater wells are curved, aswhere it is desired topass around irregularities on the ocean floor andwhere the fiowline rises off of the ocean floor to connect with thewellhead.

At present, the curved portions of flowlines communicating withunderwater well installations are limited to a minimum radius of bend,typically five feet. The term minimum bend radius is used herein todenote the smallest bend radius which permits a tool to pass through afiowline of uniform diameter in sealed relation thereto. It presents acumbersome limitation which has brought about serious problems intransporting flowlines to their underwater destination, particularlywhere the flowlines are attached to some large object such as thehousing located at the top of a wellhead. Frequently, the curvedsections of present-day flowlines are accidentally bent in handling andinstallation because of their awkward sizes. The five-foot bend systemhas the further disadvantage of making it difficult to circumventirregularities on the ocean floor without using many extra feet offiowline, which would not be required if a smaller bend radius could beutilized. Prior attempts to eliminate the problems created by thefive-foot bend system have met with little success since the known toolspassed through fiowlines are too long to pass around a bend having aradius of less than five feet.

By enlarging the internal diameter of a curved section, the tools canpass through the curve even though the bend radius is considerablyreduced. However, the tools currently used depend upon a sealingengagement with the inside walls of the fiowline in order that they maybe pumped bythe driving fluid to a desired location in the fiowline.When such tools enter a fiowline section of enlarged diameter thissealing contact with the flowline wall is lost and the tool can nolonger be forced forward by the driving fluid. Attempts have been madeto conple several short tools together as by ball joints and the like,so that the composite tool will flex around the curved fiowline ofenlarged diameter and have at least one part thereof remain in sealingcontact with those sections of the fiowline of normal diameter. This isnot a satisfactory solution because it requires the use of manyexpensive and otherwise unnecessary tool elements. Furthermore, if thesection of enlarged diameter is of appreciable length, the train ofcoupled tools becomes so heavy that the sealing elements break down andallow the driving fluid to flow past the tools. Even inexisting-fiowline systems, considerable economic saving could berealize-d if the internal diameter of the line did not have to staywithin the exact tolerances now required.

Broadly, this invention presents a solution to the aforementionedproblems by providing between the tool elements a lightweight unitaryflexible connection of sufficient length to span the section of enlargeddiameter. Preferably, the flexible connection consists of a metallicsingleor multiple-strand cable which has sufficient stiffness totransmit longitudinal compressive force from one tool element toanother. With such an arrangement, an enlarged-diameter portion offiowline can be spanned by the metallic cable in such a manner that atleast one of the tool elements is always in sealing engagement with theinside wall of a section of the flowline having normal diameter.

In this manner it becomes possible to pass fiowline tools throughflowlines of irregular diameter without major redesign of the toolelements currently in use. The invention further provides an inexpensiveand lightweight tool of simple design that can be pumped through a boreof enlarged diameter. These and other inventive features of my newdevice may be further understood by the following detailed descriptionand drawings in which:

FIGURE 1 is a diagrammatic elevation, partially in longitudinal section,illustrating a wellhead assembly'positioned on the ocean floor togetherwith one arrangement of the apparatus of the present invention;

FIGURE 2 is a pictorial view of one form of the twotool combination; and

FIGURE 3 is a diagrammatic view, partially in section, of another formof the tool.

Referring to FIGURE 1, a wellhead assembly is shown as positioned belowthe surface 11 of a body of water and preferably on the ocean floor 12.The wellhead apparatus comprises a platform 13 secured to the top of aconductor pipe or surface casing 14 which in turn extends into the earthbelow the water and is preferably cemented therein in a conventionalmanner. A conventional or suitable well casinghead, outlined at 17, ismounted on the top of the conductor pipe 14 and carries acontrol-equipment housing 18 closing the top of the casinghead and/ orany casing and tubing suspension equipment employed on the wellheadassembly, as well as the various control valves and other equipmentnormally used on the top of a Well of this type. The casinghead andhousing provide a bore 19, which is in communication with casing 14.

Emerging from housing 18 is a fiowline 20 which is sharply curved from avertical upward direction to a downward direction and thence to asubstantially horizontal direction running along the ocean floor 12.Similarly, a fiowline 21 extends from the side of casinghead 17 andassumes a position along the ocean floor 12. Flowlines 20 and 21 lead toa remote location where fluid from the Well, and normally from otherwells, is collected, metered and treated. Such a collection station maybe several miles away. Flowlines 20 and 21, in the particularinstallation illustrated, are in communication with a pair of tubingstrings 22 and 23, respectively, depending within the well. During theproduction of the well, normally only one of the flowlines or 21 isemployed in transporting fluid away from the well. The underwaterwellhead may take yarious other conventional forms such as the typeemploying Y-branched tubing as shown and described in U.S. Patent3,101,118.

As shown, fiowline 20 has an enlarged-diameter portion 24 which has abend radius of less than the minimum bend radius, e.'g., as small as twoand one-half feet when the minimum bend radius is five feet. The ends 25and 26 of the enlarged-diameter portion 24 are swaged down to the normaldiameter of the fiowline 20 and connected in fluidtight relation to thehousing 18 and line 20. Set screws 27 and 23 can be used to facilitatekeeping the swaged end 26 in tight engagement with the fiowline 20. Inlike manner, set screws 23 and 30 keep the swaged end 25 in tightengagement with housing 18. It is to be understood that otherconventional coupling means, such as hydraulic and pneumatic clamps andthreaded or welded connections, can be used in place of the set screws.

As illustrated, a first tool carrier 33 is inside of the tubing string22. Tool carrier 33 has a central mandrel 34 with axially spaced sealingelements or packers 35 and 36 mounted thereon. Packers 35' and 36 may bemade of rubber or certain plastic materials. Preferably the mandrel 34has a ball-in-socket joint 37 at a point between sealing elements 35 and36 so as to facilitate movement of the tool carrier in curved sectionsof a fiowline or pipe. Other ball=in-socket joints may be similarlyused, as at 38, to connect one or more tools to the tool carrier 33.Only one such tool, a paraflin cutter 39, has been shown. A second toolcarrier 43 with central mandrel 44, axially spaced sealing elements 45and 46, and ball-in-socket joints 47 and 48 is shown inside fiowline 20.Should the tool carrier becomestuck in a well, tool carrier 43 isprovided with a fishinghead 49 whereby a retrieving tool (not shown)attached to a wire line may be passed through the flowline 20 to latchonto fishinghead 49, thereby allowing removal of the tool carrier bypulling on the Wire line. The internal details of tool carriers 33 and43 are not the subject of my invention and may take any suitable form,such as that shown in U.S. Patent 3,052,302 to Lagucki or U.S. Patent3,050,130 to Culver et al.

A flexible cable member 50 is suitably connected at 51 and 52 to each ofthe tool carriers 33 and 43. The cable member 50 is preferably either asingleor multiple-strand metallic member of sufficient length to spanany enlargeddiameter portion of the fiowline. I prefer to use an alu-'minum cable because of its light Weight. The cable must be flexibleenough to pass around curves having a small bend radius, say two andone-half feet, without exhibiting a binding effect on the internal wallsof curved portions of the fiowline, although contact with the internalwalls is permissible. At the same time, the cable must possesssuflicient stiffness to prevent any tendency to double back upon itselfor otherwise buckle. This stiffness characteristic is especiallyimportant when the leading tool carrier is in an enlarged portion of thefiowline and out of lateral sealing engagement with the internal wallsof the fiowline. When such a situation occurs, the cable must transmitto the leading tool carrier the pushing force exerted by the drivingfluid against the trailing tool carrier. Should the cable buckle ordouble upon itself, then the trailing tool carrier might also move intothe enlarged-diameter portion of the flowline and thereby lose itssealing engagement with the internal walls of the fiowline. Due to itsstiffness the cable will normally assume a near straightline positionbetween tool carriers 33 and 43. For purposes of illustration, it hasbeen shown in a curved position in FIGURE 2. The cable 50 may beconstructed of metal, rubber, synthetic rubber, rubberized fabric,nylon, certain plastic materials, or any other material suitable for thepurpose, so long as it exhibits the required relationship betweenstiffness and flexibility referred to above.

In running one or more tools, such as paraffin cutter 39 through afiowline and down a well tubing, the tool 39 is first inserted at theorigin (not shown) of fiowline 20 with first tool carrier 33, flexiblecable 50', and the second tool carrier 43 forced in behind it. Fluidunder pressure is then pumped through the flow line 20 to drive the tooland its tool carriers down to the bottom of the well. Normally with thedriving fluid flowing in the direction of arrow 60, the pressure of thedriving fluid would, due to the construction of the carriers, act onlyagainst one of the sealing elements 45 or 46 of tool carrier 43 cansingcarrier 43 to slide through the fiowline. At this time, the sealingelements 35 and 36 of carrier 33 are being similarly acted upon by thefluid and the entire assembly moves through the fiowline. When toolcarrier 33 enters an enlarge-d diameter portion of the fiowline, thesealing contact is lost and the driving fluid passes around carrier 33.

The pushing force exerted by carrier 43 as it slides, is then'transmitted through cable member 50 to tool carrier 33, thereby movingthe entire system of elements through the fiowline. Since cable member50 is of a greater length than any enlarged diameter portion of thefiowline, the carrier 33 is pushed beyond the enlarged diameter portionand the flow of driving fluid causes one of the sealing elements of thiscarrier 33 to expand sufiiciently into sealing engagement with a portionof the fiowline having normal diameter. In this instance, tool carrier33 would now be in sealing engagement with a portion of the flowlinehaving normal diameter, and the driving fluid would push upon carrier 33and thereby transmit a pulling force in the cable 50 to pull carrier 43through the enlargeddiameter portion.

To return the tool carriers 33 and 43, with or without its accompanyingtool(s) 39, circulation of the driving fluid in the well is reversed. Inthis manner, the carriers 33 and 43 alternate-1y push and pull eachother through the irregular diameter portions back to the origin of line20.

The arrangement shown in FIGURE 3 of the drawings is a modified form oftool carrier. In this arrangement, tool carrier 53 is shown insidefiowline 54. A packer or sealing element 55 of flexible material such asrubber, is mounted on mandrel 57 and held firmly in place by flangedretaining rings 15 and 16. The mandrel has an axial passage 67. Flowpassages 58 and 59 at the ends of this passage 67 are normally closed byspring-loaded check valves 60 and 61, respectively, or any othersuitable pressureresponsive valves which are set to open at a pressurelower than that needed to propel tool carrier 53 through a flowline.Ports 63 and 64 communicate with the annular space 65. The flexiblecable 50 is shown attached to one end of tool carrier 53, and the otherend of cable 50 is attached to another tool carrier (not shown) of thetype shown at 53 in FIGURE 3. A small bleed portis shown at 66 to allowfluid to slowly escape when the carrier 53 is in an enlarged-diameterportion of the flowline; this allows radial contraction of the'sealin'gelement 55 and easy reentry into a normal diameter portion of theflowline.

When pressure fluid is passed in the direction indicatedby arrow 62, thepressure fluid flows past check valve 60 and enters fluid ports 63 and64 leading to sealing element 55. Pressure fluid entering ports 63 and64 passes into annular space 65 and forces the sealing element 55against the inner wall of fiowline 54 so that the sealing element 55acts as a piston which slides through the flowline by the application offurther pressure behind it. Similarly, carrier 53 will move in theoppoiste direction when fluid is pased into it through valve 61. Byusing one tool carrier 53 on each end of flexible cable 50, the entiresystem may be passed either forward or backward through a flowlinehaving portions of irregular diameter since, due to the length of cable50, one carrier 53 would always be in engagement with a portion of thefiowline having normal diameter.

Various changes in the details of the described system may be made,within the scope of the appended claims,

5 without departing from the spirit and scope of the invention.

I claim as my invention:

1. For use in servicing underwater oil and gas wells an apparatusadapted to be pumped through a fiowline having a major portion thereofof a given diameter and having at least one portion of enlargeddiameter, said apparatus comprising:

(a) a first tool carrier;

(b) a second tool carrier axially spaced from said first tool carrier;

(c) sealing means circumferentially mounted on each of said toolcarriers for sliding engagement With the internal walls of the majorportion of the flowline; and,

(d) an elongated flexible unitary cable member axially joining saidfirst and second tool carriers, the length of the cable member being atleast as great as the length of said enlarged diameter portion, saidcable member having sufl'icient stiffness to transmit forces ofcompression between the tool carriers without buckling.

2. In combination with the apparatus set forth in claim 1, a toolconnected to at least one of said tool carriers by articulated couplingmeans.

3. Apparatus as set forth in claim 1 wherein said flexible cable memberis a metallic cable.

4. In the method of pumping a series of tool carriers through a fiowlinehaving a major portion of given diameter and at least one portion ofenlarged diameter, wherein the carriers have peripheral sealing means ofgiven diameter for sliding engagement with the major portion of theflowline wall, the improvement of pumping the carriers through anenlarged diameter portion of flowline which comprises:

(a) placing said carriers in the fiowline in axially spaced relation atan interval greater than the length of said enlarged-diameter portion;and,

(b) maintaining the interval between the tool carriers by flexible,unitary cable means of reduced diameter whereby at least one of saidsealing means is at all times in sealing engagement with a givendiameter portion of the flowline.

References Cited by the Examiner UNITED STATES PATENTS 2,810,442 10/1957Tausch 166.5 X 3,003,560 10/1961 Corley et a1 166.5 X 3,022,822 2/1962McStravick et a1. 166.5 X 3,040,808 6/1962 Schramm et al l6677 X CHARLESE. OCONNELL, Primary Examiner. R. E. FAVREAU, Assistant Examiner.

1. FOR USE IN SERVICING UNDERWATER OIL AND GAS WELLS AN APPARATUSADAPTED TO BE PUMPED THROUGH A FLOWLINE HAVING A MAJOR PORTION THEREOFOF A GIVEN DIAMETER AND HAVING AT LEAST ONE PORTION OF ENLARGEDDIAMETER, SAID APPARATUS COMPRISING: (A) A FIRST TOOL CARRIER; (B) ASECOND TOOL CARRIER AXIALLY SPACED FROM SAID FIRST TOOL CARRIER; (C)SEALING MEANS CIRCUMFERENTIALLY MOUNTED ON EACH OF SAID TOOL CARRIERSFOR SLIDING ENGAGEMENT WITH THE INTERNAL WALLS OF THE MAJOR PORTION OFTHE FLOWLINE; AND,